vi MENDELISM 



volume on Mendel's Principles of Heredity (Cam- 

 bridge, 1909), where a full account of these matters 

 is readily accessible. Neither have I alluded to 

 recent cytological work in so far as it may bear 

 upon our problems. Many of the facts connected 

 with the division of the chromosomes are striking 

 and suggestive, but while so much difference of 

 opinion exists as to their interpretation they are 

 hardly suited for popular treatment. 



In choosing typical examples to illustrate the 

 growth of our ideas it was natural that I should give 

 the preference to those with which I was most 

 familiar. For this reason the book is in some 

 measure a record of the work accomplished by the 

 Cambridge School of Genetics, and it is not unfair 

 to say that under the leadership of William Bateson 

 the contributions of this school have been second to 

 none. But it should not be forgotten that workers 

 in other European countries, and especially in 

 America, have amassed a large and valuable body 

 of evidence with which it is impossible to deal in a 

 small volume of this scope. 



It is not long since the English language was 

 enriched by two new words Eugenics and Genetics 

 and their similarity of origin has sometimes led to 

 confusion between them on the part of those who 

 are innocent of Greek. Genetics is the term applied 

 to the experimental study of heredity and variation 

 in animals and plants, and the main concern of its 



